Microphones are used in many places and for many jobs. There is also a huge selection of microphones available, so it is necessary to buy the right microphone for the job in hand.

Knowing what is required and how to buy the best microphone is not always easy. There are different requirements for different applications.

However by looking carefully at what is needed and then matching the characteristics of the different types of microphone, it is possible to know how to buy the best microphone for any given task.

Dynamic microphone used for music vocals

Analyze what is needed

The first step when buying any microphone is to analyse exactly what is needed. Different applications have very different requirements, and different types of microphone have very different characteristics.

By matching what is needed to the characteristics of the type of microphone, the basic type can be chosen. Then it is a matter of looking at the individual specifications and buying the microphone that suits the application best.

Microphone types

When buying microphone it is useful to summarise the different types of microphone to see what is available.

Major Types of Microphone

Microphone Type

Features

Moving coil / dynamic microphone

Widely used for stage vocals, PA use, etc. This microphone is very sturdy and can tolerate comparatively rough handling. Dynamic microphones are also able to handle high sound levels without distorting. They typically have a low output impedance and a relatively high output level and they do not need an internal pre-amplifier and hence there is no requirement for phantom power. The Shure 57 and its cousins have been the mainstay for many pop groups and vocals for many years and still perform particularly well. These microphones are normally used as hand microphones and often for very close usage.

Crystal microphone

Crystal microphones or ceramic microphones are generally low cost units offering a high output voltage into a high impedance - hence the amplifier must have a high input impedance. The microphones tend to be at the bottom end of the market as they do not offer a particular wide frequency response and in view of the high impedance they are not widely used these days. The high impedance level means that the microphone cables are prone to noise and general stray pickup.

Condenser/ capacitor microphone

Condenser microphone is often used for high quality audio, both vocals and also instrumentals. It does not tolerate being overloaded well, and it requires power, both to add a bias to the capacitor and also for the preamplifier needed. They are not as robust as dynamic microphones. The output impedance is generally low to enable longer leads to be used. Prices for a useful nice microphone can range anywhere upwards from $100 to $200 to thousands of dollars, GBP or Euros, etc. When used for vocals or general voice it may be worth considering an additional pop filter to reduce pops from plosive sounds. Many microphones may have an optional one that is designed for the particular model, or a general one may be bought at the same time

Electret microphone

The Electret microphone tends to be sued for lower end microphone applications. It uses the same basic technique as the condenser microphone except that the dielectric is made from a material that holds a bias voltage and therefore it does not require external power for the microphone element itself.

Ribbon microphone

The ribbon microphone used to be the top end microphone for studio work. Now it is not as widely seen, except for high end microphones. The output is low and needs a preamplifier, and it has a very low impedance - normally as a result the microphone uses an internal step up transformer. Costs to uy are normally high.

USB microphone

This form of microphone is not really a separate technology. Often these USB microphones use a condenser insert, but incorporate a pre-amplifier and analogue to digital converter and they use a USB interface to enable the output to connect directly to a computer where the sound can be recorded. There is a variety of microphones available starting with the relatively cheap and going upwards. Some very good microphones are available which can provide some excellent recordings of vocals and instruments. A microphone in the range $100 - $200 should get a very nice USB microphone, and prices extend well up from this. These microphones are ideal for many vocals as well as for voice-overs for video, etc. It may be worth considering he use of a pop-filter as in the case of the condenser microphone above. Again many of these microphones may come with one, or there may be an option for one with the microphone. Alternatively one of the many filters that can be attached to the mic stand can be bought.

Wireless microphones

Again this is not a different type of microphone technology, but a microphone with either an embedded wireless module or one fitted externally. These can be very useful where wires can be an issue. However be aware that drop outs are more likely as signal reflections can cause the signal level to fall below what is required for the system to operate and it will drop out. Often moving slightly to one side or the other will overcome this. Also a receiver is needed and the cost of this also needs to be considered. Careful placement of the receiver antenna may be needed to overcome frequent drop-outs.

Other specifications to consider

There are other specifications to consider when buying a microphone. Even though the choice of microphone type may be straightforward, there are other aspects to consider on top of this when considering the best microphone to buy.

Major Types of Microphone

Microphone Type

Features

Directivity / directionality

The directivity or directionality of the microphone is an important factor to consider when buying a microphone. Most microphones used for vocals and PA applications have a cardioid directional pattern.

Impedance

It is necessary to ensure that the impedance is the right value when buying a microphone. Most microphones are low impedance and designed to operate into a low impedance load. However some microphones, e.g. crystal or ceramic microphones have a high impedance and the amplifier or other amplifier into which it is connected must have a suitably high input impedance, often around 1 MΩ.

Frequency response

It is necessary to ensure that the frequency response is sufficient for the applications. For some instruments like strings that may extend well down in frequency whilst also requiring a good high frequency response, the overall response may need to be very wide, necessitating a more expensive microphone. Vocals tend to require a good but not excessive frequency response.

Response flatness

Whilst it may appear that a flat response is ideal, sometimes a treble lift can be used to advantage, especially for vocals. However be aware that for PA applications, this can make the system more susceptible to howl round, where the signal from the speakers gets into the microphone and sets up a howling noise. Dynamic microphones often have some treble lift and this lends itself well to many vocals.

Cost

Cost is a major issue for anyone buying a microphone. In general the higher the cost, the better the microphone, but not always so.

However in general the manufacturers of higher end microphones like Sennheisser, AKG, R0DE and the like have many excellent microphones to offer. For more budget orientated purchases other makes are available and can offer some excellent value.

The choice of microphone to buy is dependent upon very many factors: technical, cost; aesthetics; usage and many other factors. When buying a microphone it is necessary to ensure that it meets the current requirements, and possibly some into the future. Investing in a good microphone will normally be money well spent. Sometimes economising may expedient in the short term, but not be satisfactory in the long term.